AWS WHC-3.13:2008

Electron Beam Welding
Scope : Electron beam welding (EBW) is a welding process that produces coalescence with a concentrated beam, composed of high-velocity electrons impinging on the joint. The process is used without shielding gas, except in some nonvacuum applications, and without the application of pressure. Variations of this process are high-vacuum electron beam welding (EBW-HV), medium-vacuum electron beam welding (EBW-MV), and nonvacuum electron beam welding (EBW-NV).1, 2 Since nonvacuum EBW is accomplished at near atmospheric pressure it is sometimes called atmospheric electron beam welding. Since the commercial introduction of electron beam welding in the late 1950s, the benefits of the process have been used to great advantage by industrial manufacturers. The process was first employed by the nuclear industry, and shortly thereafter by the aircraft and aerospace industries. It was quickly recognized that the process had the capacity to enhance the quality and reliability of welds that would meet the highly critical requirements of components used by these industries. An added benefit of the process was reduced manufacturing costs. During the initial period of commercial application, the electron beam welding process was limited to operating totally under high-vacuum conditions. However, new modes of operation soon were developed that did not require high vacuum to be used for the whole process, but only in the beam generation portion. This permitted the option of welding either in a medium vacuum or a nonvacuum environment. This advancement led to the acceptance of electron beam welding by commercial, automotive, and consumer product manufacturers. As a consequence, EBW has been employed in a broad range of industries worldwide since the late 1960s and has successfully demonstrated the capability of producing both very shallow and extremely deep single-pass autogenous welds (that is, without the use of filler metal) with a minimum amount of thermal distortion of the workpiece. This chapter provides an overview of the electron beam welding process and its variations, including fundamental information and the characteristics of welds produced by the process. Welding procedures, welding variables, and details of selecting welding conditions are discussed. A brief section on electron beam equipment is included in this chapter, and sections on the metals welded by the process, typical applications, and the economics of electron beam welding are presented. A discussion of safe practices specific to electron beam welding is provided. The chapter concludes with the bibliography and a list of sources of additional information on electron beam welding.